High-yielding winter synthetic hexaploid wheats resistant to multiple diseases and pests

Abstract

Development of winter wheat (Triticum aestivum) synthetics started at CIMMYT-Mexico in 2004, when winter durum wheat (Triticum turgidum) germplasm from Ukraine and Romania was crossed with Aegilops tauschii accessions from the Caspian Sea region. Chromosomes were doubled after pollination and embryo rescue, but chromosome number and cytological validation was not performed. F2 populations were grown in Mexico and were shipped to Turkey in 2008. During 2009–2015, these populations were subjected to rigorous pedigree selection under dry, cold, disease-affected environments of the Central Anatolian Plateau. The wide segregation and partial sterility observed in 2009 gradually decreased and, by 2016, most of the F8 single spike progenies demonstrated good fertility and agronomic performance. Since 2013, lines have been selected from synthetic populations and evaluated at multiple sites. Superior lines were characterized for resistance to leaf, stripe and stem rust, plant height, and reaction to common bunt and soil-borne pathogens. Thousand kernel weight of many lines exceeded 50 g, compared with the check varieties that barely reached 40 g. Threshability of synthetic lines varied from 0 to 95%, demonstrating genetic variation for this important domestication trait. Screening against Hessian fly, sunny pest and Russian wheat aphid identified several resistant genotypes. Both durum and Aegilops parents affected synthetic wheat traits. Several studies are underway to reveal the genetic diversity of synthetic lines and the basis of resistance to diseases and insects. This synthetic germplasm represents a new winter bread wheat parental pool. It is available upon request to interested breeding/research programmes.

Assessment of synthetic wheat lines for soil salinity tolerance

“…Development of winter wheat synthetics was started at CIMMYT in 2004, when winter durum wheat germplasm from Ukraine and Romania was crossed with winter Ae. tauschii accessions from the Caspian Sea basin (Morgounov et al, 2017;Gadimaliyeva et al, 2018). Independent studies indicated and confirmed that synthetic hexaploid wheat possessed considerable variation for salinity tolerance based on Na exclusion (Dreccer et al, 2004).…”

Modeling multiple phenotypes in wheat using data-driven genomic exploratory factor analysis and Bayesian network learning

“…We analyzed 16 agronomic-, 16 grain mineral-, and 13 wheat rust-related phenotypes in the current study. Agronomic traits including grain yield (GY), harvest index (HI), biomass weight (BMWT), grain volume weight (GVWT), flag leaf length (FLL), flag leaf width (FLW), flag leaf area (FLA), rachis break (RB), sterile spikelet (SP), spike length (SL), seeds per spike (SPS), spikelet number (SN), fertile spikelet (FS), spike weight (SW), grain weight per spike (GPS), and spike harvest index (SHI) were measured using previously described standard procedures (Bhatta et al, 2018a;Morgounov et al, 2018;Hussain et al, 2017). Grain minerals including arsenic (As), calcium (Ca), cadmium (Cd), cobalt (Co), copper (Cu), iron (Fe), potassium (K), lithium (Li), magnesium (Mg), manganese (Mn), molybdenum (Mo), nickel (Ni), phosphorous (P), sulfur (S), titanium (Ti), and zinc (Zn) were measured via inductively-coupled plasma mass spectrometry (ICP-MS, Agilent 7500cx, Agilent Technologies, Santa Clara, CA, USA) at the University of Nebraska Redox Biology Center, Proteomics and Metabolomics Core (Guttieri et al, 2015;Bhatta et al, 2018a).…”

“…The wheat rust (leaf stem and yellow rusts) disease severity, coefficient of infection, and infection type were tested under field conditions as previously described (Peterson et al, 1948;Morgounov et al, 2018;Bhatta et al, 2018d). Wheat rust traits collected from several locations in Turkey and one location in Kenya included the leaf rust coefficient of infection (LRCI), leaf rust infection type (LRIT), leaf rust severity (LRS), stem rust coefficient of infection at Haymana (SRCIH), stem rust infection type at Haymana (SRITH), stem rust severity at Haymana (SRSH), stem rust coefficient of infection at Kastamonu (SRCIK), stem rust infection type at Kastamonu (SRITK), stem rust severity at Kastamonu (SRSK), yellow rust coefficient of infection at Haymana (YRCIH), yellow rust infection type at Haymana (YRIH), yellow rust severity at Haymana (YRSH), and yellow rust severity at Kastamonu (YRSK).…”

International Winter Wheat Improvement Program: history, activities, impact and future

“…The segregating populations from these crosses were sent to Turkey and continuously subjected to pedigree selection under drought stress and disease pressure. The resulting synthetics combined high grain yield under moisture stress with resistance to rust, common bunt, soil-borne pathogens and insect pests [31] . A set of 130 winter synthetics was selected for cooperative PhD study with the University of Nebraska-Lincoln.…”